BI-DIRECTIONAL GLASS PASSIVATED JUNCTION TRANSIENT VOLTAGE SUPPRESSOR 1500 WATTS, 6.8 THRU 200 VOLTS# Technical Documentation: 15SMC24CA Transient Voltage Suppressor (TVS)
Manufacturer : VISHAY
Component Type : 15kW SMC Series Transient Voltage Suppressor Diode
Document Version : 1.0
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## 1. Application Scenarios
### Typical Use Cases
The 15SMC24CA is designed for robust transient voltage protection in demanding electronic systems. Primary applications include:
- Surge Protection : Safeguards sensitive ICs against voltage transients from electrostatic discharge (ESD), lightning-induced surges, and inductive load switching
- Power Supply Protection : Installed across AC/DC power inputs to suppress voltage spikes exceeding normal operating ranges
- Data Line Protection : Protects communication interfaces (RS-232, RS-485, Ethernet) from transient overvoltage events
- Automotive Systems : Provides load dump protection in automotive electronics where high-energy transients occur during alternator field decay
### Industry Applications
- Telecommunications : Base station equipment, network switches, and communication infrastructure
- Industrial Automation : PLCs, motor drives, and control systems exposed to industrial electrical noise
- Consumer Electronics : High-end appliances, gaming consoles, and premium audio/video equipment
- Automotive Electronics : ECU protection, infotainment systems, and charging infrastructure
- Renewable Energy : Solar inverters and wind power systems susceptible to lightning strikes
### Practical Advantages and Limitations
Advantages:
- High Power Handling : 15,000W peak pulse power capability (10/1000μs waveform)
- Fast Response Time : Typically <1.0 picosecond reaction to transient events
- Low Clamping Ratio : Provides effective voltage limiting during surge events
- Bidirectional Operation : Protects against both positive and negative voltage transients
- Robust Packaging : SMC (Surface Mount Ceramic) package offers excellent thermal performance
Limitations:
- Parasitic Capacitance : ~1500pF typical capacitance may limit high-frequency signal line applications
- Physical Size : SMC package (7.1mm × 6.2mm) requires adequate PCB space
- Voltage Derating : Operating at maximum ratings requires thermal management considerations
- Cost Consideration : Higher per-unit cost compared to smaller TVS devices
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## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Inadequate Current Path Design
- Problem : High surge currents causing trace damage or device failure
- Solution : Implement wide, short PCB traces (minimum 80 mil width) between TVS and protected circuit
Pitfall 2: Thermal Management Neglect
- Problem : Repeated surge events causing thermal runaway
- Solution : Incorporate thermal vias under device and ensure adequate copper pour for heat dissipation
Pitfall 3: Incorrect Voltage Selection
- Problem : Selecting device with too high VWM, reducing protection effectiveness
- Solution : Choose VWM slightly above normal operating voltage (24V device for 12-20V systems)
### Compatibility Issues with Other Components
Protection Coordination:
- Ensure TVS breakdown voltage is below the maximum voltage rating of protected ICs
- Coordinate with fuses/circuit breakers to ensure TVS activates before other protection devices
- Avoid parallel connection with MOVs without proper coordination studies
Signal Integrity Considerations:
- High capacitance may affect high-speed data lines (>100MHz)
- For sensitive analog circuits, consider lower capacitance TVS alternatives
- Ensure TVS doesn't introduce unacceptable leakage current in low-power applications
### PCB Layout Recommendations
Placement Strategy:
- Position TVS device as close as possible to the point of entry (connector, power input)
- Minimize inductance in the protection path by keeping trace
